Probabilistic DNA evidence: the layperson’s interpretation

A recent Australian High Court case held it was acceptable to express DNA results as either a frequency ratio or as an exclusion percentage. In order to understand if these two approaches could affect the outcome of a criminal trial, this study collected online survey data from the general public who were eligible for jury duty in Australia (n = 258). Participants were randomly assigned and completed two vignettes with two different forensic results that were manipulated in a 2×2 between-group design. Results found the way evidence was presented was sometimes statistically significant on the verdict in the case, and when not, the relationship was going in the predicted direction. Specifically when evidence was presented as an exclusion percentage, participants were more likely to convict than when presented with frequency ratio evidence. This is important as research suggests that once DNA evidence is admitted the effect can be difficult to undo, even with extensive cross-examination and testimony. DNA is a valuable tool for the criminal justice system; however, this study considers whether there is a need for standardisation in the way results are presented in a criminal trial to ensure jurors do not fallaciously reason about the evidence.     

Traumatic lumbar hernia: can’t afford to miss

We describe the radiological and surgical correlation of an uncommon case of a traumatic lumbar hernia in a 22-year-old man presenting to the emergency department following a motor vehicle accident. Computed tomography (CT) of the abdomen revealed a right-sided traumatic inferior lumbar hernia containing a small amount of fat through the posterior lateral internal oblique muscle with hematoma in the subcutaneous fat and adjacent abdominal wall musculature, which was repaired surgically via primary closure on emergent basis. The purpose of this article is to emphasize the importance of diagnosing traumatic lumbar hernia on CT and need for urgent repair to avoid potential complications of bowel incarceration and strangulation.     

Dystrophic intracranial calcification: CT evidence of ‘cerebral steal’ from arteriovenous malformation

Summary Two cases of dystrophic intracranial calcification due to arteriovenous malformations (AVM) are reported. The characteristic distribution is in the watershed areas and away from the AVM. Deposition of calcium on ischaemic brain tissues as a result of cerebral steal by the AVM is the probable pathogenetic mechanism.     

Rate of liver volume increase: can it predict recipient prognosis after left lobe transplantation from living related donors?

PURPOSE: The purpose of this study was to determine whether liver volume increase can predict recipient outcome. MATERIALS AND METHODS: Size-matched left lobe transplantation was performed for 16 patients. Computed tomography was performed in Week 1 after transplantation. Rate of liver volume increase was compared between survivors and deceased subjects. RESULTS: Mean rate of liver volume increase was significantly higher for survivors than for fatalities. CONCLUSION: Rate of liver volume increase might be useful for predicting outcome of living donor liver transplantation.     

Brain metastases after stereotactic radiosurgery using the Leksell gamma knife: can FDG PET help to differentiate radionecrosis from tumour progression?

Stereotactic radiosurgery (SRS) using the Leksell gamma knife promotes acute and chronic local changes in glucose metabolism. We have been able to find very few papers on Medline on the subject of assessment of metastases by 2-[(18)F]fluoro-2-deoxy- D-glucose positron emission tomography (FDG PET) after SRS. The aim of this work was to specify the additional value of FDG PET, in comparison with magnetic resonance imaging (MRI), in differentiating SRS-induced radionecrosis from viable brain metastasis in a clinical setting. Fifty-seven metastases in 25 patients were treated by SRS. An average of 33 weeks later, all the patients underwent FDG PET. At the same time (SD=2 weeks) all the patients underwent MRI. The sensitivity, specificity and accuracy of both FDG PET and MRI examinations were calculated with reference to clinical and radiological follow-up or biopsies. The additional value derived from use of FDG PET after MRI was assessed and progression-free survival rates were compared. The difference in progression-free survival rates between the negative and positive subgroups was significant ( P=0.0005) for MRI and even more so ( P<0.00001) for FDG PET. Sensitivity, specificity and accuracy were 75% (6/8), 93.9% (46/49) and 91.2% (52/57) for FDG PET, and 100% (8/8), 65.3% (32/49) and 70.2% (40/57) for MRI. In the subgroup of patients with positive or non-diagnostic MRI, the probability of presence of a viable tumour was only 32% (8/25). This probability increased to 100% (5/5) when subsequent FDG PET was positive and decreased to 11.1% (2/18) when FDG PET was negative. The frequency of a viable neoplasm was significantly different ( P=0.001) in the FDG PET negative and positive subgroups. MRI and FDG PET both have an important predictive value for persistent viable metastases after treatment by SRS. Neither sensitive but non-specific MRI nor specific but insensitive FDG PET is reliable on its own. While FDG PET significantly improved the diagnostic accuracy in the subgroup of patients with positive and non-diagnostic MRI, it provided no additional value in the MRI-negative subgroup.     

Letter to the Editor: On “Advantages and disadvantages of stiffness instructions when studying postural control” by C.T. Bonnet: You just can’t win: Advantages and disadvantages of the postural stability requirement

In the examination of postural control, instructions to stand as still as possible are common and promote a relatively unnatural sway pattern. The validity of the stability requirement is discussed in the present commentary in response to the discussion initiated by Cedrick T. Bonnet. The advantages of using the stability requirement include: evaluating unbiased postural control, reducing variability in postural sway, manipulating focus of attention, examining the ability to maintain an upright stance, and ecological validity of testing. The disadvantages include: constraining natural postural sway, increasing the complexity of the control condition, promoting an internal focus of attention, and reducing the ability to detect exploratory behaviour. After evaluating the aforementioned advantages and disadvantages, the present commentary suggests that researchers should strive to provide specific instructions to maintain feet, arm and eye position without specifically requiring participants to reduce their postural sway.     

Expected frequencies,exclusion percentages and ‘mathematical equivalence’: the probative value of DNA evidence in Aytugrul v The Queen

In Aytugrul v The Queen the High Court held that it was acceptable to express the strength of DNA evidence in terms of an exclusion percentage. A key reason of the Court was that this was equivalent to the expected frequency of the DNA profile. This article assesses these two measures from a mathematical perspective. While the two are closely related, the frequency measure is to be preferred. The exclusion percentage fails to adequately capture the difference in probative value between DNA profiles of different frequencies.     

Age estimation from the sternal end of the fourth rib: A study of the validity of İşcan’s Method in Tunisian male population

The aim of this study was to assess the fourth rib phase İşcan method on a Tunisian sample.One hundred and eight (108) specimens of sternal ends of fourth ribs of Tunisian male population were collected during forensic autopsies performed in the Department of Forensic Medicine and Pathology of the University Hospital Fattouma Bourguiba of Monastir. Two operators, independently, assigned each rib to İşcan’s phase. The data obtained by the two operators were analyzed using SPSS 17.0 and MedCalc. The repeatability and accuracy of İşcan method was tested by kappa coefficient (κ), for each operator.Spearman correlation coefficient (R), between estimated İşcan phase and İşcan phase relative to chronological age, was good with values of 0.758 (CI: 0.664–0.828) and 0.717 (CI: 0.611–0.798) for operator 1 and operator 2, respectively. The perfect agreement, between İşcan phase related to chronological age and İşcan phase estimated by both operators, was found for phases fewer than 5. Intra-observer agreement was highest for both operators with kappa value of 0.73 for operator 1 and 0.71 for operator 2. The estimation of the observers fell within one phase from the ideal and there was minimal disparity. A good accuracy between operator 1 and operator 2 was found (κ = 0.747, p = 0.057). In order to improve the results, we have pooled ages in five new phases. The correlation, between new age groups and İşcan phase estimated by both operators, was moderate. We conclude that İşcan method can be applicable in Tunisian population with a good correlation for age ranges under 39 years.     

Spin transfer from protein to DNA in X-irradiated ’dry‚ and hydrated chromatin: an electron spin resonance investigation of spectral components between 77K and room temperature

Purpose : To investigate the potential total and relative free-radical transfer from histones to DNA in X-irradiated chromatin, by analysing the relative contributions of individual radicals from protein and from DNA. Materials and methods : Chromatin was isolated from calf thymus, freeze-dried and either used as such or after equilibration at 76% relative humidity. A mixture of histones was purchased. Xirradiation was performed at 77K (liquid nitrogen). Data acquisition was on a Bruker ESP 380 ESR-spectrometer (X-band, 9.5GHz) and at high magnetic fields (285 GHz, Y-band, GHMFL Grenoble). Data analysis involved computer treatment of spectra. Results : Three components were isolated from an annealing series of histones and assigned to specific radicals (X-band). Chromatin revealed the existence of radicals from both DNA, as well as from the histone compartment. The presence of the oxidized guanine base, as well as the reduced cytosine and thymine bases from DNA at 77 K was confirmed by high-field ESR. Relative radical yields were determined by superposition of individual components from DNA and histones in order to give complete reconstructions of the experimental spectra of the annealing series. Conclusions : The relative yields of individual radicals in chromatin differ from those in histones or DNA, respectively. Their behaviour upon annealing is, on the other hand, not significantly changed. Since the total radical yield of DNA radicals is about two times higher in the chromatin complex than in pure DNA, the hypothesis of spin transfer from protein to DNA prior to radical stabilization at 77 K is substantiated.     

The role of <Superscript>18</Superscript>F-FDG PET/CT in the assessment of suspected recurrent gastric cancer after initial surgical resection: can the results of FDG PET/CT influence patients’ treatment decision making?

Purpose  

¹⁸F-fluorodeoxyglucose (FDG) PET/CT has been widely used for staging, re-staging and for monitoring therapy-induced changes and response to therapy in patients with various types of cancer, but its utilization for gastric cancer has been limited. The purpose of this study was to evaluate the clinical role of FDG PET/CT in the detection of gastric cancer recurrence as compared with diagnostic CT and to assess the impact of FDG PET/CT results on patients’ treatment planning.